Hi Raul,
Let’s have a look:
Your router options are:
- Cisco 2800 series routers, including the Cisco 2801, Cisco 2811, Cisco 2821, and Cisco 2851
- Cisco 3800 series routers, including the Cisco 3825 and Cisco 3845
- Cisco IAD2430 series routers
- Cisco UC520-x series routers
The UC520 series is nice and not too noisy but it’s about ~$300 on eBay. The 2800 series are cheap nowadays…I see some for around ~$70 on eBay but they do make a lot of noise. Sometimes people remove the fans, not something I would officially recommend but you might be able to get away with it 
For the configurations, you can follow along with the lessons in the courses. For example:
The first lesson where you need your hardware is this one:
It explains how to connect to the console, access the CLI, etc. In each lesson where we configure something, I walk you through the exact commands.
Hope this helps!
Rene